1. Field of the Invention
This invention relates to the art of testing pressure vessels for leaks and specifically deals with a leak testing device which easily engages and seals off an inlet of a pressure vessel having an out-turned peripheral rim and an interior seat where air may be injected through the leak testing device to determine the presence of any leaks in the pressure vessel itself. Such devices are used, for example, in the testing of automobile radiators where the inlet has a neck with an out-turned peripheral rim and an interior seat which is sealed off by the device. Air is injected into the radiator through the leak testing device and the radiator is then submersed into a liquid, such as water. If any leaks exist in the walls of the radiator, air will escape from any such leaks and will be visible to an observer as bubbles rising in the water.
2. Prior Art
Existing leak testing devices are generally comprised of a resilient stopper which engages an inner seat of the inlet of a pressure vessel, such as a radiator, to seal off the inlet where the device has a central aperture which permits air to be forced therethrough into the vessel. These devices are normally affixed to the radiator by a cap which is threaded onto the outer threads of the neck of the inlet whereby the stopper is forced into engagement with the interior seat of the inlet by a spring compression mechanism as the cap is threaded onto the inlet neck. Such devices normally require a significant downward force on the cap to compress the spring before the threads can be engaged as well as a downward force to remove the cap.
Other devices are comprised of a resilient stopper which seals off the vessel inlet by expanding within the throat of the vessel. Expansion of the resilient stopper is usually provided by a nut which is threaded on one end of a central stem which in turn extends through the stopper. When tightened, the nut moves toward a base plate on the opposite end of the stopper thereby compressing and expanding the stopper outwardly therebetween. In either case, these existing stoppers are difficult to engage, do not provide sufficient adjustability and do no adequately seal off the inlet of the vessel.